Refrigerating apparatus



March 5, 1940. TQBE Y 2,192,850

REFRIGERATING APPARATUS Filed Sept. 2, 1958 2 Sheets-Sheet 1- INVENTOREAYMQND E Toss-x.

ATTORN WITNESSES:

March 5, 1940. R. E. TOBEY REFRIGERATING APPARATUS 2 Sheets-Sheet 2Filed Sept. 2, 1938 0 0 ON C O Z0 PDU hEO kou Z0 PQU mun-3Z5) I Hi;- am0 on GM Q 0 o 9 ON on o om ow INVENTOR EQYMGND E. TGBE-Y.

ATTORN Patented Mar. 5, 1940 UNlTED STATES,

REFRIGERATING APPARATUS Raymond E. Tobey, Springfield, Mass., assignorto Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,a corporation of Pennsylvania Application September 2, 1938, Serial No.228,072

17 Claims.

My invention relates to refrigerating apparatus and has for an object toprovide improved apparatus of this kind. C

It is a further object of my invention to maintain the mean temperatureof the air in a refrigerated zone substantially constant irrespective ofchanges in temperature of the air exteriorly of the zone and thedifferent rates. of heat leakage into the zone which accompany suchtemperature changes.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in accordance with theaccompanying drawings, in which:

Fig. 1 is a diagrammatic view of a refrigerating machine constructed andarranged in accordance with my invention;

Fig. 2 is an enlarged sectional view of a detail taken along the lineIIII of Fig. 1; and

Figs. 3 and 4 are charts'showing temperatures of several elements of theapparatus when cycled under two different ambient temperatures.

Reference will now be had to Figs. 1 and 2 of the drawings wherein Ihave shown my invention applied to a refrigerator of the domestic typeand including an insulated cabinet structure Ill having a front wall IIand a rear wall I2. The variouswalls of the cabinet structure I0,including the front wall II and rear wall I2, are defined by inner andouter shells I3 and I ll, having heat insulatingmaterial I5 disposedtherebetween.

The cabinet structure In embodies a chamber I6 for storing the food tobe refrigerated. An access opening I I is provided in the front wall IIand is closed by a suitable insulated door structure I8. Heat isabstracted from the air in the chamber It by means of an evaporator I9which may be of conventional construction and supported in any wellknown manner. As shown, the evaporator I9 is carried by a bracket 2|secured to a plate 22, the latter being carried by the rear wall I2 ofthe cabinet within the chamber I6.

The plate 22, in cooperation with a plate 23 I carried on the outside ofthe rear wall I2, closes an opening 24 formed in the rear wall throughwhich the evaporator I9 is passed during its assembly to the cabinetstructure. Heat insulating material 25 is disposed between the plates 22and 23 for retarding the flow of heat from the ambient atmospherethrough the opening 24 as is well understood.

Circulation of refrigerant through the evaporator I9 is effected by acompressor 26, driven by an electric motor 21. Refrigerant vaporized inthe evaporator I9 is withdrawn by the compressor 26 through a suctionconduit 28 and compressed to a relatively high pressure. The compressedgas is conveyed through a conduit 29 to a condenser 3| wherein it iscooled and condensed. Cooling of the condenser is effected in anysuitable manner, such as, for example, by means of a motor driven fan32.

Condensed refrigerant is conveyed from the condenser 3| through asuitable expansion device, shown by way of example as an elongated tube33 of the so-c'alled capillary type. The tube 33 discharges the expandedrefrigerant into an inlet conduit 34 that communicates with theevaporator I9. The expanded, condenser refrigerant discharged from thetube 33 enters an inlet portion 35 of the conduit 34, which portion 35is dis-. posed exteriorly of the refrigeranted zone I6 and preferably,intermediate the plates 22 and 23. It will be understood that theconduit 34 and its portion 35 define a part of the low pressure side ofthe system which includes the evaporator I9.

It will be apparent from the foregoing descrip tion that therefrigerating apparatus which I have disclosed operates on thewell-known com-v pressor-condenser-expander cycle.

Operation of the motor 21 and compressor 26 is thermostaticallycontrolled by means of a thermostat, generally indicated at 36 andincluding an expansible bellows 31, a pivoted arm 38 actu- V atedthereby and an adjustable spring 39 disposed in opposition to thebellows.

A switch M for controlling operation of the motor 21 is actuated by themovable arm 38, preferably through a snap-acting mechanism 42. As iswell understood, the switch 4! is closed and \opened, respectively, whenpredetermined high temperature obtaining in the coldest portion of theconduit 43. p

In accordance with my invention, a portion 44 of the conduit 43 isdisposed in heat transfer relation with the air in the chamber I6 and asecond portion, indicated at 45, is disposed in heat transfer relationwith the atmosphere exteriorly of the cabinet I0. Preferably the conduitportion is disposed within the opening 24 adjacent the plate 23 whereits temperature is affected by the temperature of the ambient atmosphereexteriorly of the cabinet I0. It will be apparent that the flow of heatfrom the ambient atmosphere through the plate 23 to the conduit portion45 in- The conduit portions 44 and 45 define relatively small reservoirsfor the liquefied portion of the fluid contained in the conduit 43. The

charge of fluid in the conduit 43 and bellows 31 is such, that at thelowest expected temperature of any part of the conduit 43, the amount ofcondensed fluid present therein is less than the capacity of eitherreservoir 44 or 45. It will be understood that, in a system charged inthis manner, the fluid condenses in the portion thereof of lowesttemperature and the pressure of the fluid in the system is a function ofthe temperature of the liquefied portion of the fluid. For example, ifthe reservoir 44 is the lowest temperature portion of the conduit 43,the fluid condenses therein and its temperature determines the pressurein the bellows 31. Accordingly, the thermostatic switch 4| is controlledin accordance with the temperature of the reservoir 44 and, therefore,the temperature of the air in the chamber l6. As described hereinafter,the temperature of the reservoir 45 may be depressed to a value belowthe temperature of the reservoir 44. Accordingly, the fluid condenses inthe reservoir 45 so that the pressure in the conduit 43 and bellows 31is depressed to a value corresponding to the temperature of thereservoir 45. Condensed fluid in the reservoir 44 therefore vaporizes atthe lower pressure and condenses in the reservoir 45. At this time, theoperation of the thermostat switch 4| is responsive to the temperatureof the reservoir 45.

As shown, the reservoir portion 45 of the tube 43 is also disposed inheat transfer relation with the inlet conduit portion 35 so that thetemperature of the reservoir 45 is determined conjointly by thetemperatures of the ambient atmosphere and the inlet conduit portion 35.Preferably, an adjustable fin 46 connects the inlet conduit portion 35and the reservoir 45 and defines a path for the flow of heattherebetween. As best shown in Fig. 2, the fin 46 is defined by sections41 and 48 connected, respectively, to the reservoir 45 and the conduitportion 35 and secured together by a bolt 49. One of the sections 48 isslotted as shown at 5| to receive the bolt 49 so that the sections 41and 48 may be adjusted relative to each other whereby the length of thefln 46 may be varied. Accordingly, the rate of heat transfer between thereservoir 45 and the inlet conduit 35 is adjusted so that the coolingeffect of the conduit 35 upon the reservoir portion 45 is varied. Itwill be understood that the fln 46 is permanently adjusted duringtesting of the apparatus to provide proper compensation and need not beadjusted in service.

The conduit 34 which defines a portion of the low side of the system isof relatively small mass and has low heat storage capacity. Duringoperation of the compressor 26, the temperature of the conduit 34 isdepressed to a relatively low value. Heat is abstracted at this timefrom the fln 46 and reservoir portion 45 of the control tube 43, therate of heat transfer being determined by the adjustment of the fin 46,so that the temperature of the reservoir 45 is depressed to a valuebelow the temperature of the reservoir 44. Accordingly, the temperatureof the reservoir 45 determines the pressure in the conduit 43 andbellows 37 so that operation of the compressor 26 is terminated inresponse to a predetermined low temperature of the reservoir 45, whichtemperature is affected conjointly by the temperatures of the ambientatmosphere and'the conduit portion 35.

During inactive periods of the compressor 26, flow of condensedrefrigerant is substantially stopped. As the conduit portion 35 isdisposed exteriorly of the refrigerated chamber l6 in a relatively warmregion, its temperature increases more rapidly than the temperature ofthe evaporator |9. Accordingly, the temperature of the reservoir 45rises above the temperature of the reservoir 44, whereupon the latterassumes control. As described heretofore, the pressure in the bellows 31at this time is a function of the temperature of the reservoir 44 and,therefore, the compressor 26 is started in response to a predeterminedtemperature of the reservoir 44. It will be apparent from the foregoingdescription that the compressor is started in response to thetemperature of the air in the chamber l6 and is stopped in response,conjointly, to the temperatures of the conduit portion 35 and theambient atmosphere exteriorly of the chamber IS.

The refrigerating apparatus described heretofore will maintain thetemperature of the air in the chamber l6 at substantially constantmaximum and minimum values irrespective of changes in the ambientatmosphere exterior of the chamber and the difierent rates of heatleakage into the chamber, which accompany changes in ambienttemperature. The mean temperature of the evaporator l9, however,fluctuates with ambient temperature changes. The mean temperature of theevaporator I9 is relatively low during periods when the ambienttemperature is high and, conversely, the mean evaporator temperature isrelatively high when the ambient temperature is low. The curves shown inFig. 3 indicate the temperatures of the reservoirs 44 and 45, the liquidline 35 and the evaporator l9 throughout a cycle of operation with anambient temperature of 65 F. The corresponding curves in Fig. 4 show thetemperatures of these elements during a cycle of operation when theambient temperature is 110 F. Further reference to these curves will bemade hereinafter under the description of operation which follows.

Operation V As shown in the drawings, the thermostatic switch 4| is openso that the compressor 26 is inactive. As described heretofore, thetemperature of the reservoir 45 is higher than the temperature of thereservoir 44 so that the thermostatic switch 4| is under control of thereservoir 44. When the temperature of the air in the chamber I6 and,therefore, the temperature of the reservoir 44, rises to a predeterminedvalue of, for example, 41 F., the thermostatic switch 4| is closed forinitiating operation of the compressor 26. Vaporization of refrigerantin the evaporator IQ is initiated for abstracting heat from the air inthe chamber I6. It will be assumed that the temperature of the ambientatmosphere is at the relatively low value. of, for example, 65 F. sothat the rate of heat leakage into the chamber |6 through the cabinetstructure is at a relatively low value. The temperature curve for thereservoir 44 is shown at A, Fig. 3. At the time of starting thecompressor, the temperature of the reservoir 45 is approximately 46 F.as shown by curve B. The temperature of the portion 35 of the liquidline 34 is approximately ..43 F. as shown by the curve C. As shown byCurve D, the temperature of the evaporator at this time is 34 F.Duringoperation of. the compressor, the temperature of the reservoir 45is rapidly depressed by the cold inlet conduit 3435 to a value below thetemperature of the as shown by the curve.

reservoir 44 so that the reservoir 45 becomes the controlling point ofthe thermostat 36. Operation of the compressor is terminated when thetemperature of the reservoir is depressed to 29 F. as shown by the curveB at which time the tem-' perature of the evaporator 19 is T F. As therate of heat leakage into the chamber I6 is relatively low withanambient temperature of 65 F., the heating of the reservoir 45 thereby islow and the temperature of the reservoir is rapidly -de' pressed wherebythe compressor is operated for a relatively short time of approximately2 minutes During operation of the compressor it will be apparent fromcurve A that the temperature of the air in the chamber 16 is depressedto a value of approximately 39 F. so that the average temperature of theair between cut-on and cut-off periods is approximately 40 F.

During inactive periods of the compressor, the temperature of all of theelements recited in the foregoing description increases as shown by thecurves A, B, C, and D. Heating of the reservoir 45 by the ambientatmosphere is effected at this time and its temperature increases to a'value higher than the temperature of the reservoir 44 at thefifteen-minute period as indicated on the chart of Fig. 3. Accordingly,at this time, the control point of the thermostat 36 is transferred tothe reservoir 44. Operation of the compressor is again initiated whenthe temperature of the air in the chamber I6 and therefore thetemperature of the reservoir 44 increases to a value of 41 F. as shownby the curve A, this operation being effected at approximately theforty-six minute position on the chart. The complete cycle of operationhas now been described for an ambient temperature of 65 F.

The operation of, the apparatus under high ambient temperatureconditions is similar to that described. The temperatures of thereservoirs 44, 45, the evaporator l9, and the liquid line portion 35 areindicated by the curve A, B, C and D of Fig. 4. It will be understoodthat, as shown by the curve A, operation of the compressor is startedwhen the temperature of the air in the chamber 16 rises to a value of 41F.

As the ambient temperature is relatively high, the fiow of heat to thefin 46 is high so that the temperature of the reservoir 45 is 61 F. atthis time. With a F. ambient temperature, the temperature in theevaporator I9 is approximately 19 F. at starting. The temperature of theinlet conduit portion 35 is 51 F. at starting and is quickly depressed,as shown by the curve C. Accordingly, heat is abstracted from thereservoir 45 at a high rate and, after approximately two minutes ofoperation, its temperature is depressed below the temperature of thereservoir 44. Operation of the compressor continues until thetemperature of the reservoir 45 is depressed to the cut-off temperatureof 29 F. at which time the compressor is stopped as describedheretofore. The period of operation of the compressor is approximatelyseven minutes with a 110 ambient temperature compared with.approximately two minutes with a 65 F. ambient temperature.

At the time of stopping the compressor, the

temperature of the evaporator is approximately -1 F. as shown by thecurve D, due, of course, to the relatively long period of operation.During inactive periods of the compressor, the temperature of thereservoir 45 increases rapidly, due to the relatively high ambienttemperature, so

closely follows the temperature of the air in the I chamber [6.Operation of the compressor is again initiated when the temperature ofthe air in the chamber [6 and of the reservoir 44 increases to a .valueof 41 F. At the time of starting the compressor, the temperature of theevaporator is 19 F.

It will be apparent from the foregoing description that, when theambient temperature is at a relatively high value of 110 F., a completecycle of operation is eifected in approximately twenty minutes which isrelatively short when contrasted with the 46 minute cycle effectedduring operation under 65 F. ambient temperature conditions. It willalso be noted that under both high and low ambient temperatures, the airtemperature is maintained between 39 F. and 41 F. whereby an averagecabinet temperature of 40 F. is effected. The different rates of heatleakage into the chamber I6 are compensated for by the different meanevaporator temperatures as clearly shown in charts of Fig. 3 and, Fig.4.

The charts shown in Figs. 3 and 4 are plotted from test data of arefrigerating machine constructed generally along the lines of theapparatus shown in Figs. 1 and 2. It will be apparent that thetemperatures and duration of the cycle will vary with differentmachines. The temperatures of the various elements set forth are for asingle position of the adjusting handle 40 andwill vary, of course, forother positions thereof, it being understood that the mean temperatureof the air in the zone I6 is varied as the handle 40 is moved to itsdifferent positions.

I have shown the thermostat reservoir 45 and fin 46 connected to theevaporator conduit portion 35 within the insulation intermediate theinner and outer plates 22 and 23. In this position the temperature ofthe reservoir 45 is readily affected by ambient temperature changesalthough not directly subjected to the ambient atmosphere. Accordingly,condensation of moisture from the room atmosphere is not effected by thefin 46 and conduit portion 35 during the periods when their temperaturesare below the dew point temperatures of the ambient atmosphere. It willbe understood, however, that this-showing is by way of example and thatthese elements may be disposed otherwise in accordance with myinvention.

Furthermore, forms of thermostats other than the specific form disclosedmay be employed in accordance with the invention; it being understoodthat any suitable thermostatic mechanism is applicable that responds torefrigerated air temperature for initiating operation of the apparatusand which is responsive, conjointly, to refrigerant temperature andtemperature of the ambient atmosphere for terminating operation of theapparatus.

I have shown the control tube reservoir portion 45 connected to theinlet conduit of the evaporator but it will be understood that otherportions of the low pressure side of the system of small mass may beconnected thereto. It will be understood that, while I have shown arefrigerating system having a device of the so-called capillary type forthe expansion of refrigerant, my

invention is not so limited and may be applied 75 to apparatus employingother types of expansion devices.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited but is susceptible ofvarious changes and modifications without departing from the spiritthereof and I desire, therefore, that only such limitations shall beplaced thereupon as are imposed bythe prior art or as set forth in theappended claims.

What I claim is:

1. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated, evapan evaporator for-abstracting heat from theairin said zone, refrigerant condensing means, means for conveyingcondensed refrigerant from the condensing means to the evaporator andincluding a portion of the evaporator of. relatively small mass disposedexteriorly of the zone, thenmostatic means responsive to the temperatureof the refrigerated media in said zone for initiating operation of the.refrigerant condensing means and responsive primarily to the temperatureof said evaporator portion for terminating operation thereof.

3. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated, an

evaporator for abstracting heat from the media in said zone, means forcirculating refrigerant through the evaporator and including a conduitfor conveying liquid refrigerant to the evaporator, said conduitextending exteriorly of the zone be-- ing refrigerated, and meansresponsive to the temperature of said media for initiating operation ofthe refrigerant circulating means and responsive primarily to thetemperature of a portion of the conduit exteriorly of the refrigeratingzone for terminating operation of the same.

4. In refrigerating apparatus, the combination of an insulatedcabinetdefining a zone to be re-' frigerated, cooling means for abstractingheat from the air in the zone, means for translating refrigerant to thecooling means and including a conduit having a portion disposedexteriorly of said zone, thermostatic means responsive primarily to thetemperature of the air in the zone for starting operation of therefrigerant translating means and responsive conjointly to thetemperatures of the atmosphere exterior of the zone and of said conduitportion for terminating operation of the refrigerant translating means.

5. In refrigerating apparatus, the combination of an insulated cabinetfor defining a zone to be refrigerated, an evaporator for abstractingheat from the air in said zone, refrigerant condensing means disposedexteriorly of the zone, means for conveying liquid refrigerant from thecondensing means to the evaporator and including a conduit of relativelylow heat storage capacity and defining a .portion of the evaporator,said conduit having a portion thereof disposed exteriorly of therefrigerated zone so that its temperature is affected by the temperatureof the ambient atmosphere, and thermostatic means for initiatbeingcooled and for terminating operation of a the same in response to thetemperature of said conduit portion.

6. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated, an evaporator for abstracting heat from said zone,means for condensing refrigerant vaporized in the evaporator, anexpansion device for reducing the pressure of the condensed refrigerant,said evaporator having a portion of relatively small mass disposedexteriorly of the zone for receiving the condensed refrigerant from theexpansion device, and thermostatic means for initiating operation of thecondensing means in response to the'temperature of the media cooled bythe evaporator and for terminating operation thereof conjointly inresponse to the temperatures of said evaporator portion of small massand of the atmosphere exteriorly of said zone.

7. In refrigerating apparatus, the combination of a cabinet having aninner shell for defining a zone to be cooled and an outer shell spacedfrom the inner shell, an evaporator for abstracting heat from said zone,means disposed exteriorly of said zone for condensing refrigerantvaporized in said evaporator, means for conveying condensed refrigerantfrom the condensing means to the evaporator and including a conduit ofrelatively small mass disposed at least in part between said shells, andthermostatic means for controlling the operation of the refrigerantcondensing means and including a gas filled member having a firstportion thereof disposed in the media in said zone and a second portiondisposed in heat transfer relation with the conduit and intermediatesaid shells.

8. The combination as claimed in claim 7 including a fin interposedbetween said conduit and the second portion of the gas filled member.

9. In refrigerating apparatus, the combination of means defining a zoneto be cooled, an evaporator for abstracting heat from said zone, meansfor translating refrigerant through the evaporator and including aconduit connected to the evaporator, said conduit having a portionthereof extending exteriorly of the zone being cooled and in heattransfer relation with the atmosphere exterior of the zone, said conduitportion being depressed in temperature during operation of thetranslating means to a value below the temperature of the media beingcooled in said zone and, during inactive periods of thetranslatingmeans, said conduit portion being heated by the atmosphere exterior ofthe zone to a temperature in excess of the temperature of the media inthe 'zone, and means for controlling the operation of the translatingmeans and including a gas filled th'ermostatic member having respectiveportions thereof disposed in heat transfer relation with the media beingcooled and with said conduit portion.

- 10. In refrigerating apparatus, the combination of means defining azone to be refrigerated, cooling means for abstracting heat from themedia in said zone, said cooling means including a portion of relativelysmall mass extending exteriorly of said zone, means for circulatingrefrigerant through said cooling means, and thermostatic means forinitiating operation of the circulating means in response primarily tothe temperature of the media being refrigerated and for terminatingoperation of the circulating means in response 76- the cooling device ofsmall mass at rates bearing a predetermined relation to the temperatureof the atmosphere exteriorly of said zone, and thermostatic means forcontrolling operation of the refrigerant translating means and having aheat responsive element disposed in heat transfer relation with themedia being refrigerated and with said portion of the cooling device ofsmall mass, said thermostatic means being so constructed and arrangedthat operation of the refrigerant translating means is initiatedprimarily in response to a predetermined temperature of said media beingrefrigerated and is terminated primarily in response to a predeterminedtemperature of the portion of the cooling device of small mass.

12. In a mechanical refrigerator, the combination of an insulatedcabinet, a cooling unit therefor effective to cool the media in saidcabinet, a mechanism for supplying refrigerant to said cooling unit,automatic control means for starting the supply of refrigerant from saidmechanism to the cooling unit when the temperature of the media rises toa predetermined value and for normally stopping the supply ofrefrigerant substantially independently of the temperature of the mediaa substantial time interval after starting, said time interval beingdetermined conjointly by the temperature of the refrigerant in thecooling unit and the temperature of the atmosphere exteriorly of thecabinet.

13. In refrigerating apparatus, the combinationof means defining a zoneto be refrigerated, evaporating means, at least part of which abstractsheat from the media in said zone and including a portion disposed inheat transfer relationship with the ambient atmosphere, said portion ofthe evaporating means increasing in temperature more rapidly than themain portion of the evaporator during inactive periods of therefrigerating apparatus, means for translating refrigerant through theevaporating means and thermostatic means responsive to the temperatureof the meina being cooled for initiating operation of the refrigefanttranslating means and responsive primarily to the temperature of saidportion of the evaporator which is disposed in heat transferrelationship with the ambient atmosphere for terminating operation ofthe refrigerant translating means.

14. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated, evaporating means, atleast part of which abstractsheat from the media in said zone and including first and secondportions, the latter of which increases more rapidly than the formerduring inactive periods of the refrigerating apparatus, means fortranslating refrigerant through the evaporating means and thermostaticmeans responsive to the temperature of the media in said zone forinitiating operation of the refrigerant translating means and responsiveprimarily to the temperature of said portion of the evaporating meanswhich increases in temperature more rapidly for terminating operation ofthe refrigerant translating means.

15. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated, evaporating means, at leastpart of which abstractsheat from the media in said zone, intermittently operated means fortranslating refrigerant to the evaporating means, said evaporating meanshaving first and second portions, said second portion of the evaporatingmeans increasing and decreasing in temperature more rapidly than thefirst portion during periods when the refrigerant translating means isinactive and active, respectively, a thermostatic regulator forinitiating and terminating operation of the refrigerant translatingmeans, said regulator including a gas-filled expansible element havingrespective heat responsive portions disposed in heat transfer relationwith the media being cooled and with said second portion of theevaporating means, the charge of gas in said element being such that atnormal operating temperatures the amount of condensed gas in the elementis less than the capacity of either of the heatresponsive portions,'whereby the operation of the thermostatic regulater is in response tothe temperature of the coldest of said heat responsive portions, andmeans for conveying heat from the ambient atmosphere to said second heatresponsive element in amounts varying directly with changes oftemperature of the ambient atmosphere.

16. In an intermittently operated refrigerating apparatus, thecombination of aninsulated cabinet, a cooling unit associated therewith,means for supplying refrigerant to said cooling unit, and a control forsaid supplying means comprising a volatile control liquid in heatconducting relationship primarily with the air in said cabinet at leastafter said air has been cooled and the refrigerant supply hassubstantially been terminated, means responsive to an increase inpressure of said control liquid above a predetermined point for startingthe flow of refrigerant to said cooling unit, and automatic means fornormally stopping said flow of refrigerant a substantial time intervalafter the starting of said flow and independently of the temperature ofthe air in said cabinet.

1'7. In refrigerating apparatus, the combination of an insulatedcabinet, a cooling unit associated therewith, means for supplyingrefrigerant to said cooling unit, and a control for said supplying meanscomprising a tube having a portion in heat conducting relationshipprimarily with the air in said cabinet, said portion becoming thecoldest portion of said tube after the cabinet has been cooled and afterthe refrigerant supply from said supplying means has terminated, saidtube comprising a second portion in heat exchange relationship with boththe cooling unit and the ambient atmosphere of said cabinet, said secondportion being cooled to a temperature below that of the first portion bythe cooling unit when supplied with refrigerant, said ambienttemperature warming said second portion to a temperature above that ofthe first portion after the supply of refrigerant to the cooling unithas ceased.

RAYMOND E. TOBEY.

CERTIFICATE OF CORRECTION.

Patent No. 2,192,850. March 5, 19110.

RAYMOND E. 'ToBEY. It is hereb; certified that error appears in theprinted specification of the above nimibered patent requiring correctionas follows: -Page 1, second column, line-9, for the word "condenser"read condensed; page 5, first column, line 66, claim 171, before "more"insert in temperature; and that the said Letters Patent should be readwith this correction therein that the same may conform to the record ofthe case in the Patent Office.

Signed and sealed this 9th day of April, A. D. l9hO Henry Van Arsdale,(Seal) Acting Commissioner of Patents

